Where to install LR 5

I am subscribed to CC which says its the latest version of LR but then why is this not the latest version?

What makes you think that your version 4.4 of Lightroom Desktop is not the latest version? Have you perhaps not subscribed to the correct plan? There are two main subscription plans: the Photography Plan, or the Lightroom-only Plan.

The Photography Plan includes Lightroom Classic (current version 10.4), Photoshop, all the Lightroom Ecosystem products (see later for details), and 20GB of cloud storage.

The Lightroom-only Plan includes all the Lightroom Ecosystem products, plus 1TB of cloud storage.

Since 2017, there have been two versions of "Lightroom" running in parallel:

1. The "traditional" Lightroom which manages locally-stored images, and has some (but limited) interaction with the Adobe Cloud. Renamed in 2017 to be known as Lightroom Classic, and often shortened to Classic or LrC. It can be used on both MacOS and Windows10 systems.

2. Then there is the Lightroom cloud-based "ecosystem", which is a series of "client" apps which run on different platforms and all of which would seamlessly sync to a central cloud-based server. The server manages the cloud-based assets and controls the flow of information to/from any connected client app. The available client apps are:

• Lightroom for Mac/Win (currently version 4.4), can be run on computers (desktop, laptop) which run either the MacOS or Windows10 operating systems. This is the app which caused most of the naming confusion when it was released, and was often nick-named "Cloudy" to differentiate it from Classic. Personally I prefer the Adobe informal naming of Lightroom Desktop, or LrD for short.
• Lightroom for Mobile, of which there are several different versions - for iOS phones, for iPads running iPadOS, for Android devices. Usually just called Lightroom Mobile (or LrM for short) but because there are some small differences between the iOS/iPadOS and Android versions, it's sometimes necessary to be more specific when referring to the app.
• Lightroom Web (LrWeb or even LrW for short) - can be run in most browsers, and is a direct window into the central cloud server. All the other apps have a local catalog which may reflect a different position to the central server when there are syncing issues, so LrW is the "go-to" app for investigating sync problems. It's also the best place for managing shared albums.
• Lightroom for Apple TV - hardly ever gets mentioned, either because it never has issues, or hardly anyone uses it.

Because of the 10-year difference in ages between Classic and the Lightroom Desktop app, it's inevitable that Classic is currently much more feature-rich than Lightroom Desktop, perhaps that's why you think you might not be running the "latest version"?

Lightroom 4.4  is the current version of the Lightroom Ecosystem Desktop Client. 

Lightroom 5.0 is a very old version of the current Lightroom Classic Client (released in 2013).  

They are completely different programs. 

Because of the relative ages of the two separate software lifespans they are overlapping version numbers.